Unusual Topological RNA Architecture with an Eight-Stranded Helical Fragment Containing A‑, G‑, and U‑Tetrads
journal contributionposted on 08.02.2017, 00:00 by Chao-Da Xiao, Takumi Ishizuka, Xiao-Qing Zhu, Yue Li, Hiroshi Sugiyama, Yan Xu
Human telomeric RNA performs various cellular functions such as telomere length regulation, heterochromatin formation, and chromosome end protection. Using a combination of nuclear magnetic resonance, circular dichroism, and gel electrophoresis, we observed an unusual topological structure formed by human telomere RNA r(GUUAGGGU). Our results showed that every set of four strands formed a parallel G-quadruplex as symmetry-related units containing four G-tetrads, two U-tetrads, and one A-tetrad. An eight-stranded helical fragment containing A-, G-, and U-tetrads provided a central intercalated scaffold that connected two G-quadruplex units in an alternating antiparallel arrangement, giving rise to a novel RNA architecture. This higher order RNA structure is so stable that it would be surprising if similar structures do not occur in nature. Our findings provide a new insight into the behavior of human telomeric RNA molecules.
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chromosome end protectiontelomere length regulationtopological structuregel electrophoresisG-quadruplex unitseight-stranded helical fragmentheterochromatin formationsymmetry-related unitsEight-Stranded Helical Fragment ContainingRNA moleculesorder RNA structureantiparallel arrangementnovel RNA architectureintercalated scaffoldUnusual Topological RNA Architecture